Juicing: Body Cleansing or Nutrient Depleting?

Juicing and juice cleanses are a popular trend, touted for their detoxing, weight loss, and health benefits, which promise to energize you by providing a daily dose of fruits and vegetables. What is the verdict of juicing?

Juicing and juice cleanses are a popular trend, touted for their detoxing, weight loss, and health benefits, which promise to energize you by providing a daily dose of fruits and vegetables. There are a plethora of options, from grab-and-go single bottles to juice cleanses that replace a week’s worth of food. Is this trend really living up to its predicted effects? Is there a difference between juicing and blending? Although juicing may increase intake of vegetables and fruits, it may not really be as glamorous as it sounds – it may even be dangerous if it becomes a continuous habit.

What is Juicing?

Juicing is a process where juice is extracted from fruits and vegetables, such as through pressing or squeezing. This is different from eating whole fruits and vegetables or blended drinks because juicing leaves only liquid while discarding the fiber filled pulp. [1] Learn more about the importance of fiber in the constipation article of this issue on page 10 of this issue. According to the United States Department of Agriculture (USDA), it is recommended that during meals, half of the plate should consist of fruits and vegetables. [2] Juicing provides a way to simplify these daily needs, since one bottle can contain extracts of multiple fruits and vegetables and is fast and easy to consume.

Juicing vs. Blending

Pros of Blending

Cons of Blending

Unlike juicing, blending retains all of the edible portions of the fruit or vegetable in the drink. A 2014 study published in Preventive Nutrition and Food Science found that blended drinks consisting of apples, pears, persimmons, and mandarin oranges exhibited stronger antioxidant activity and greater amounts of phenolic compounds than those prepared by juicing. [3] Phenolic compounds are molecules that contribute to antioxidant activity, which have shown to be inversely correlated with the risk of chronic diseases when abundant in one’s diet. [4]

Since blended drinks contain all of the fibers of the original fruits and vegetables, these may quickly contribute to excess fiber if one’s diet is not monitored properly. Too much fiber can lead to intestinal gas, abdominal bloating, and cramping. Water intake should also increase alongside increased fiber intake to aid stool formation. [5]

Pros of Juicing

Cons of Juicing

Short term

In the 2014 Preventive Nutrition and Food Science study, results revealed that ascorbic acid, or Vitamin C, content was higher in drinks prepared by juicing rather than blending. In particular, the juice of apples, pears, and mandarin oranges contained the most ascorbic acid content. [3] Thus, nutrient and antioxidant levels, such as Vitamin C, can differ based on juice extraction techniques.

Short term

Since juicing removes the rinds of fruits and vegetables, it also removes fibers but keeps all the sugars. [7] For example, consider a fresh, medium sized apple that has 19 g of sugar and 4 g of fiber. In comparison, a glass of apple juice does not contain any fiber and may contain juice from multiple apples, thus increasing the total sugar content (1 cup of apple juice contains about 24 g of sugar). [8] Since fiber is necessary for regulating blood sugar levels, drinking fruit juice may result in blood sugar spikes. [9] Furthermore, fiber is also necessary to activate satiety responses, so drinking a cup of fruit juice may not be as filling as eating a piece of fruit. [8]

Long term

A 2011 study published in Nutrition Journal found that individuals who drank 16 oz, or 2 cups, of carrot juice every day for 3 months significantly increased total antioxidant capacity in their blood plasma, which means there was increased antioxidant activity in their bloodstream (similar to the effects of blended drinks). [6]

Long term

The fructose present in fruit juice can be problematic as it is associated with increased triglyceride formation in liver cells. Triglycerides are a form of fat that can result from the breakdown of fructose in the liver. Increased triglycerides can impair liver function and build up as plaque inside artery walls when released into the bloodstream. Since higher intakes of fructose are associated with obesity and heart disease, drinking fruit juice in moderation can limit these risks. [10] Dietary Guidelines for Americans recommends no more than one serving, or 4 oz, of 100% fruit juice as part of the daily fruit intake. [11]

Juice Cleansing

1.What is it?

Juice cleansing is a process in which an individual consumes only vegetable and fruit juices for a period of 3 to 10 days. [12] However, there are some juice cleanses on the market that last just 1 day as well. Some juice cleansing regimens also suggest that no other additional food items are necessary during the process.

2.Effects

PositiveA 2009 study published in Proceedings of the Nutrition Society found that consumption of the equivalent of 5 servings of fruits and vegetables in the form of purée and fruit juice concentrates in intervals over an 8 hour time period increased dietary phytochemicals, micronutrients, and plasma antioxidant status. [7] Similar to antioxidants, phytochemicals have antioxidant-like functions which may help ward off disease. [13] Additionally, the micronutrients found in juices are essential for maintaining tissue function. [14]

NegativeMany juice cleansing companies state that no additional food is necessary to supplement the juice cleanse. However, as mentioned previously, juice can have increased sugar content and does not contain the fibers originally present in whole fruits and vegetables, which can leave you feeling hungry and cause sugar spikes. When blood sugar is high, red blood cells stiffen and interfere with blood circulation, resulting in a buildup of cholesterol within blood vessels over time. [15] In addition, a juice cleanse may contain very little protein because fruits and vegetables generally do not contain as much protein as animal meat, legumes, or dairy products. Thus, a full day cleanse may not meet the Center for Disease Control and Prevention’s daily recommended dietary allowances of 46 g of protein for women and 56 g for men. [16] While one day probably will not cause any damage, multiple days on a juice cleanse can lead to protein deficiency.

Sometimes a cleanse contains a bottle of nut milk in the regimen that can account for some of the lacking protein, fiber, and healthy fats, but this is usually not enough to meet the recommended daily allowances. Also, nuts are an incomplete protein source, meaning that they lack some of the essential amino acid building blocks necessary for a healthy diet. [16] As a consequence, these missing nutrients from a juice cleanse may be responsible for the fatigue and headaches reported by some users.

Bottom lineJuicing can be highly promoted by the media, and there may even be some benefits as you are including more fruits and vegetables in your diet. However, in reality, drinking a lot of juice or going on a juice-only cleanse may have some adverse effects. The lack of fiber, protein, and increased sugar consumption during a juice cleanse may lead to sugar crashes and leave you feeling hungry and tired. Furthermore, drinking fruit juice too frequently may increase blood sugar and triglycerides in the long run. Although drinking fruit and vegetable juices that contain vital nutrients has been shown to increase overall antioxidant activity in the body, it may be considered healthier to consume fruits and vegetables in their original form as part of a balanced intake.

References

Juicing for Health and Weight Loss. webmd. (2014).

What Foods Are in the Fruit Group?. choosemyplate.gov. (2014).

Effects of chronic and acute consumption of fruit- and vegetable-puree-based drinks on vasodilation, risk factors for CVD and the response as a result of the eNOS G298T polymorphism. P Nutr Soc. (2009).